diff options
Diffstat (limited to 'db2/btree/bt_search.c')
| -rw-r--r-- | db2/btree/bt_search.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/db2/btree/bt_search.c b/db2/btree/bt_search.c index a21a8208bc..c39c9af322 100644 --- a/db2/btree/bt_search.c +++ b/db2/btree/bt_search.c @@ -47,7 +47,7 @@ #include "config.h" #ifndef lint -static const char sccsid[] = "@(#)bt_search.c 10.8 (Sleepycat) 10/25/97"; +static const char sccsid[] = "@(#)bt_search.c 10.9 (Sleepycat) 11/18/97"; #endif /* not lint */ #ifndef NO_SYSTEM_INCLUDES @@ -119,12 +119,20 @@ __bam_search(dbp, key, flags, stop, recnop, exactp) return (ret); } - /* Decide if we need to save this page; if we do, write lock it. */ + /* + * Decide if we need to save this page; if we do, write lock it. + * We deliberately don't lock-couple on this call. If the tree + * is tiny, i.e., one page, and two threads are busily updating + * the root page, we're almost guaranteed deadlocks galore, as + * each one gets a read lock and then blocks the other's attempt + * for a write lock. + */ if (!stack && ((LF_ISSET(S_PARENT) && (u_int8_t)(stop + 1) >= h->level) || (LF_ISSET(S_WRITE) && h->level == LEAFLEVEL))) { (void)memp_fput(dbp->mpf, h, 0); - if ((ret = __bam_lget(dbp, 1, pg, DB_LOCK_WRITE, &lock)) != 0) + (void)__BT_LPUT(dbp, lock); + if ((ret = __bam_lget(dbp, 0, pg, DB_LOCK_WRITE, &lock)) != 0) return (ret); if ((ret = __bam_pget(dbp, &h, &pg, 0)) != 0) { (void)__BT_LPUT(dbp, lock); |